Touch Screen Electrode Pitch Optimization for Peripheral Sensing
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Solution Overview
Problem
The existing touch screen designs suffer from reduced sensing accuracy and increased errors in detecting hovering or touching objects in the peripheral area due to lower electrode density and resulting capacitance changes, leading to larger detection errors compared to the normal area.
Innovation Solution
The design incorporates multiple first and second electrodes in parallel axes with specific overlapping configurations and pitch adjustments, including a double or single layer structure with bridging connections, and utilizes a touch sensitive processing apparatus with difference value circuits to enhance detectability and mitigate electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If touch electrodes are arranged with fixed pitch in the peripheral area, then manufacturing is simplified, but sensing accuracy deteriorates due to lower electrode density
Solution Approach 1:
The patent applies different pitch values to different regions of the touch screen. The peripheral area uses a first pitch while the normal area uses a second pitch, making the electrode density non-uniform. This local differentiation allows higher electrode density in the peripheral area to improve sensing accuracy, while maintaining simpler fixed-pitch arrangements in other areas.
Solution Approach 2:
The touch screen is divided into two distinct regions: a peripheral area and a normal area. Each region is assigned different electrode pitch parameters. This segmentation allows independent optimization of electrode density for each region, resolving the contradiction between manufacturing simplicity and sensing accuracy in the peripheral area.
2Measurement precision
If electrode density is increased in the peripheral area, then sensing accuracy improves, but device complexity increases
Solution Approach 1:
Instead of uniformly increasing electrode density across the entire screen, the patent applies higher density (first pitch) only to the peripheral area where sensing accuracy is most needed. The normal area maintains the second pitch, thus improving peripheral sensing without proportionally increasing overall device complexity.
Solution Approach 2:
The touch screen is segmented into peripheral and normal areas with different electrode configurations. This allows the system to concentrate complexity only where necessary (peripheral area with first pitch) while keeping other areas simpler, thus improving sensing accuracy without proportionally increasing overall device complexity.
3Ease of manufacture
If edge pitch is increased for frame clearance, then ease of assembly improves, but detection accuracy deteriorates due to fewer capacitance changes
Solution Approach 1:
The patent applies a smaller first pitch specifically to electrodes near the frame in the peripheral area, increasing electrode density in this critical region. This local enhancement ensures sufficient capacitance changes for accurate detection near the frame, while other areas maintain larger pitch values for easier assembly and manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves detection accuracy in the peripheral area by reducing errors and electromagnetic interference, allowing for more precise detection of external objects hovering or touching the screen, while also simplifying manufacturing and reducing material costs.
Implementation Method 1
The touch sensitive processing apparatus may detect external objects such as fingers or styli which are hovering or touching the touch screen by utilizing capacitance sensing principles
Data Source
AI summary
A touch screen which is provided comprising: a display; multiple first electrodes in parallel to a first axis and multiple second electrodes in parallel to a second axis, wherein the first and the second electrodes are overlapped with the display; and an opaque and non-conductive frame which surrounds and overlaps on top of edges of the display, wherein the first axis is perpendicular to the second axis, the first electrodes intersect with the second electrodes, a distance between center lines of any two adjacent second electrodes is a second pitch, a distance in the first axis between a center line of the first one of the second electrodes and a second edge of the frame in parallel to the second axis is less than or equals to a quarter of the second pitch, a distance in the first axis between a center line of the last one of the second electrodes and a fourth edge of the frame in parallel to the second axis is less than or equals to a quarter of the second pitch.